Maximus
Natural Depletion in a Three Well Development

For small oil and gas reservoirs (e.g. 5-20 barrels recoverable) which are typical in mature provinces such as the North Sea , a common development concept is natural depletion. This development concept is perhaps the least costly of all the concept types and is therefore ideal for small reservoirs which are often unable to sustain the investment required to implement enhanced recovery systems.

Example of a Natural Depletion LOF Model of a 3 Well Development

This example is of a three well natural depletion scheme where the flow rate from the wells is commingled in a production manifold before export along a 5 km production pipeline. The production pipeline is insulated with an overall heat transfer coefficient or U-value of 4 W/m/K. The system was simulated for a period of ten years and takes about 40 seconds to complete.

Maximus has an elegant integrated dynamic plotting capability which allows the User to specify any number of plotters containing whichever variables are of interest. When the User starts the simulation, the plotters are automatically generated and updated as simulated data are produced. For this example the two plotters were defined to look at the FPSO arrival temperature and the gas and oil flow rates. These plots are shown below. In this simple example, it can be seen that the oil and gas rates are initially 22,000 bbl/d and 12.5 MMft3/d respectively, dropping to less than 4,000 bbl/d and 2 MMscfd after ten years. From the plot of arrival temperature, it is apparent that the temperature drops markedly with the flow rate. Indeed, after about six years the temperatures is below 40C which could raise concerns about possible wax deposition later in field life.